Apparatus and method for testing jet engine fuel manifold flow distribution

ABSTRACT

An apparatus and method for testing the flow distribution through a turbine engine fuel manifold and one or more nozzles connected to the manifold. A plurality of individual fluid measurement vessels, at least one for each of the nozzles being tested, collects test fluid pumped through the manifold and the connected nozzles. The level in each of the measurement vessels is periodically sampled during the test. The test fluid flow rate through each of the nozzles is periodically determined based on the periodically sampled levels.

RELATED APPLICATIONS

[0001] This is a divisional of and claims priority from application Ser.No. 09/960,897 entitled “Apparatus and Method For Testing Jet EngineFuel Manifold Flow Distribution”, filed Sep. 21, 2001, which isincorporated herein by reference.

BACKGROUND OF THE INVENTION

[0002] The present invention relates to an apparatus and method fortesting jet engine fuel manifolds and, more particularly, to anapparatus and method for testing the flow distribution in jet enginefuel manifolds.

[0003] Modern jet aircraft use turbofan jet engines to generate thethrust that moves the aircraft on the ground and through the air. One ofthe major components of the turbofan engine is the combustor. Thecombustor receives compressed air from the compression portion of theengine, mixes the air with fuel supplied from fuel injector nozzles, andignites the fuel/air mixture in a combustion chamber, therebysignificantly increasing the energy of the air flowing through theengine. The high-energy air exiting the combustor expands through aturbine, which drives the compressor, and through a nozzle, to providethrust.

[0004] The fuel injector nozzles that supply the fuel to the combustionchamber are coupled to a manifold that is located circumferentiallyaround the engine. If fuel flow through the injector nozzles is uneven,for example if fuel flow through one or more of the fuel injectornozzles is significantly higher than other nozzles, large temperaturevariations in the hot gas that exits the combustor and impinges upon theturbine will result. These large temperature variations cause unwantedstresses in the turbine, which leads to early replacement of costlyturbine components, including the combustors, transition liners, andturbine nozzles.

[0005] Uneven fuel flow through the injector nozzles is caused byvarious defects. For example, if a portion of the manifold, or one ormore of the injector nozzles, becomes clogged, then fuel flow throughthe remaining injector nozzles will be higher than the others.Additionally, after usage one or more of the injector nozzles may wear,resulting in a larger nozzle opening than the other injector nozzlescoupled to the manifold.

[0006] In order to check for uneven fuel manifold flow distribution, thefuel injector manifolds are periodically removed from the engines andsubject to flow distribution testing. Presently, this testing isconducted using one of two known test devices. One of these test devicesconsists of a test stand that includes one measurement vessel for eachinjector nozzle. To conduct the test, the fuel manifold and injectornozzles are removed from the engine and are connected to the test stand.A test fluid is then pumped into the manifold and through the injectornozzles, and a predetermined minimum volume of test fluid is collectedin each of the individual measurement vessels. After the predeterminedvolume is collected, test fluid flow is stopped and an operator observeshow much fluid is collected in each of the individual measurementvessels. The operator then compares the volumes accumulated from eachnozzle and calculates the flow distribution as [(max-min)/max]×100, toensure this is below the limit.

[0007] Another known test device also consists of a test stand thatincludes a measurement vessel for each injector nozzle. However, each ofthe measurement vessels has a pair of associated optical level sensors.To test a fuel manifold with this device, the fuel manifold and injectornozzles are removed from the engine and are connected to the test stand.A test fluid is then pumped into the manifold and through the injectornozzles, and is collected in each of the individual measurement vessels.As the rising level in each vessel passes the lower optical sensor, ahigh frequency clock begins counting; as the level reaches the upperoptical sensor, the clock stops, and test fluid flow is stopped. Acomputer determines the flow rate through each of the nozzles based onthe time required to fill each vessel to a known volume.

[0008] Each of the above-described methods and apparatuses for testingfuel manifold flow distribution has its disadvantages. The first testdevice and method exhibits a large measurement uncertainty (e.g., +/−2%repeatability), due in large part to the operator subjectivity in themeasurement and to the coarse graduations of the measuring vessels. Thislarge amount of uncertainty limits the ability of engine maintenance andtesting facilities to accurately determine when fuel distributionmanifolds are actually exhibiting uneven flow distribution. Although thesecond test device alleviates the operator subjectivity somewhat, itstill suffers numerous disadvantages. For example, the measurementvessels used with this device are opaque and, therefore, do not allow anoperator to view the spray pattern of the test fuel as it exits theinjector nozzles. In addition, the level sensors used in the device donot provide real-time level sensing and display throughout the test.Thus, an operator will not be able to clearly detect a fault in thesystem and abort the test, until after the predetermined time period haselapsed. In addition, the device is not configured as a closed loopsystem, which means that the test fluid pumped through the fuel manifoldand into the measurement vessels is not conveniently drained or pumpedback to the reservoir from where it originated.

[0009] Hence, there is a need for a fuel distribution manifold testdevice and method that improves upon one or more of the drawbacksidentified above. Namely, a device and method that provides increasedaccuracy and repeatability, and/or provides real-time level sensing anddisplay throughout the test, and/or allows operators to view the fuelnozzle spray patterns during the test, and/or is provided in a closedloop system configuration.

SUMMARY OF THE INVENTION

[0010] The present invention relates to an apparatus and method fortesting the flow distribution through a turbine engine fuel manifold andone or more nozzles connected to the manifold. One embodiment of thepresent invention allows an operator to view individual measurementvessel levels, view real-time flow data through each of the nozzles, andsimultaneously view the fuel nozzle spray patterns throughout the test.

[0011] In one aspect of the present invention, an apparatus for testingfluid flow distribution through a turbine engine fuel manifold and oneor more fuel nozzles connected thereto includes a test fluid supplytank, one or more test fluid supply lines, a plurality of fluidmeasurement vessels, a plurality of level sensors, and a computer. Thetest fluid supply lines each include a test fluid inlet in fluidcommunication with the test fluid supply tank and a test fluid outletadapted to be coupled to the fuel manifold and its connected fuelnozzles. The plurality of fluid measurement vessels are each operable toreceive a test fluid discharged from one of the fuel nozzles when thefuel manifold is coupled to the test fluid supply line outlet. Theplurality of level sensors are individually coupled to each of the fluidmeasurement vessels and are operable to determine a level of the testfluid therein and generate a level signal representative of the testfluid level. The computer is coupled to the one or more level sensorsand is operable to periodically sample each of the generated levelsignals and calculate test fluid flow rate through each of the fuelnozzles based on the sampled level signals.

[0012] In another aspect of the present invention, a method of testingfluid flow distribution through a turbine engine fuel manifold and oneor more fuel nozzles connected thereto includes supplying a test fluidto the fuel manifold at a predetermined pressure, and collecting thetest fluid discharged from each of the fuel nozzles in separatemeasurement vessels. The volume of test fluid discharged from each ofthe fuel nozzles is periodically determined until each of themeasurement vessels have collected a predetermined volume of the testfluid. The test fluid flow rate through each of the fuel nozzles isperiodically calculated based on the periodically determined test fluiddischarge volume.

[0013] In yet another aspect of the present invention, acomputer-readable storage medium containing computer executable code forinstructing a computer, which is coupled to a test stand that isconfigured to test fluid flow distribution through a turbine engine fuelmanifold and one or more fuel nozzles, and that includes a plurality offluid measurement vessels each operable to receive a test fluiddischarged from one of the fuel nozzles, to perform the steps ofperiodically determining and displaying a volume of test fluiddischarged from each of the fuel nozzles until each of the measurementvessels have collected a predetermined volume of the test fluid, andperiodically calculating and displaying test fluid flow rate througheach of the fuel nozzles based on the periodically determined test fluiddischarge volume.

[0014] Other independent features and advantages of the preferred sensorwill become apparent from the following detailed description, taken inconjunction with the accompanying drawings which illustrate, by way ofexample, the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015]FIG. 1 is a simplified schematic cross section view of a turbofanjet engine;

[0016]FIG. 2 is a perspective view of a jet engine fuel manifold thatmay be used in the turbofan jet engine depicted in FIG. 1;

[0017]FIG. 3 is a front view of a machine for testing fuel manifold flowdistribution according to an embodiment of the present invention;

[0018]FIG. 4 is a schematic representation of a test fluid supply unitwhich forms a portion of the machine depicted in FIG. 3;

[0019]FIG. 5 is a schematic representation of a flow test unit whichforms a portion of the machine depicted in FIG. 3;

[0020]FIG. 6 depicts a cross section side view of a single measurementvessel taken along line 6-6 of FIG. 3;

[0021]FIG. 7 depicts a front view of a control unit which forms aportion of the machine depicted in FIG. 3;

[0022]FIG. 8 depicts a block diagram of the circuitry associated witheach of the various sensors used in the machine depicted in FIG. 3;

[0023]FIG. 9 depicts a block diagram of the circuitry associated witheach of the various pumps and control valves used in the machinedepicted in FIG. 3;

[0024]FIG. 10 depicts a block diagram of the circuitry associated withvarious remotely controlled throttle valves used in the machine depictedin FIG. 3;

[0025]FIG. 11 illustrates an exemplary user interface screen displayprovided on a display device which forms a portion of the control unitdepicted in FIG. 7;

[0026]FIGS. 12A and 12B depict a process for testing jet engine fuelmanifold flow distribution using the machine depicted in FIG. 3; and

[0027]FIG. 13. depicts an example of the content and format of acomputer printout providing the results of the testing processesdepicted in FIGS. 12A and 12B.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0028] A simplified schematic cross section view of a turbofan jetengine is depicted in FIG. 1. As this figure illustrates, a turbofan jetengine 100 consists of six major parts or sections. These major parts orsections are a turbofan 102, a bypass section 104, a compressor 106, acombustor 108, a turbine section 110, and an outlet nozzle 112.

[0029] The turbofan 102 is positioned at the front, or “inlet” section101 of the engine 100, and induces air from the surrounding environmentinto the engine 100. The turbofan 102 accelerates a fraction of this airinto and through the bypass section 104, and out the outlet nozzle 112.The remaining fraction of air that is not directed through the bypasssection 104 is directed toward the compressor 106, which raises thepressure of the air to a relatively high level. This high-pressurecompressed air then enters the combustor 108, where a ring of fuelinjector nozzles 114 injects a steady stream of fuel. The injected fuelis ignited by a burner (not shown), which significantly increases theenergy of the high-pressure compressed air.

[0030] The high-energy compressed air then flows from the combustor 108into the turbine section 110, causing rotationally mounted turbineblades 111 to turn and generate energy. The energy generated in theturbine section 110 is used to power other portions of the engine 100,such as the turbofan 102 and compressor 106. The air exiting the turbinesection 110 then leaves the engine 100 via the outlet nozzle 112. Theenergy remaining in this exhaust air aids the thrust generated by theair flowing through the bypass section 104.

[0031] As was previously noted, the fuel injector nozzles 114 thatsupply the fuel to the combustor section are coupled to a manifold thatis located radially about the engine 100. An exemplary embodiment of onesuch fuel manifold 200 is illustrated in FIG. 2. The particular manifoldassembly 200 depicted in FIG. 2 consists of a matched set of manifoldsub-assemblies 202, 204, one for each side of the combustor 108. Eachmanifold assembly 202, 204 includes a plurality of flexible conduitsets, consisting of a primary conduit 206 and a secondary conduit 208,interconnecting the individual fuel injector nozzles 114 a-l.

[0032] The fuel injector nozzles 114 a-l are generally identical, inthat each includes a body portion 115, and separate internal primary andsecondary flow paths (not depicted) that direct fuel through a nozzleportion 117. However, as can be seen in FIG. 2, the fuel injectornozzles 114 a-l are not all identical externally. More particularly,while each of the fuel injector nozzles 114 a-e and 114 g-k includes aninlet port 212 and an outlet 214 for primary fuel flow, and an inletport 216 and an outlet port 218 for secondary fuel flow, end fuelinjector nozzles 114 f and 114 l includes only a primary 212 and asecondary 216 inlet port, and no outlet ports. In addition, the otherend fuel nozzles 114 a and 114 f are shaped differently from theremaining injector nozzles 114 b-e and 114 h-k, in that its primary 212and secondary 216 inlet ports are positioned to conveniently couple themanifold sub-assemblies 202, 204 to the aircraft's fuel distributionsystem (not shown).

[0033] During normal operation of the engine 100, when both primary andsecondary fuel flow (referred to as “combined flow”) is used, fuelenters the end fuel nozzle 114 a and 114 g via their primary 212 andsecondary 216 inlet ports. A portion of the fuel is ejected out thenozzle portion 117, and the remaining portion is directed out theprimary 214 and secondary 218 outlet ports. The primary and secondaryfuel flow is then coupled to the next nozzles 114 b, h via the primary206 and secondary 208 fluid conduits, respectively. The primary andsecondary fuel flow through the remainder of the fuel nozzles 114 b-eand 114 h-k is identical until it reaches the end fuel nozzles 114 f and114 g, which have no outlets other than their nozzle portion 117. Fuelflow through each of the manifold sub-assemblies 202, 204 is similarwhen only primary, or only secondary, fuel flow is used, except thatfuel does not flow in and through the non-used portions of the manifoldsub-assemblies 202, 204. In other words, if only primary fuel flow isbeing used, such as during engine start-up or idle operations, then fuelflows through only the primary flow path portions of the fuel nozzles114 a-l and manifold sub-assemblies 202, 204. Conversely, if onlysecondary fuel flow is being used, which is rare (if at all) duringnormal engine operations, then fuel flows through only the secondaryflow path portions of fuel nozzles 114 a-l and the manifoldsub-assemblies 202, 204.

[0034] The fuel manifold assembly 200, as was previously noted, isperiodically removed from the engine 100 and subject to flowdistribution testing. This testing is accomplished by connecting thefuel manifold sub-assemblies 202, 204 to a testing machine, anddetermining the flow distribution through each of the fuel nozzles 114a-l. One such machine, which is the subject of the present invention, isdepicted in FIGS. 3-11, and will now be discussed in detail.

[0035] Referring first to FIG. 3, a front view of a machine for testingfuel manifold flow distribution, according to a preferred embodiment, isdepicted. The test machine 300 includes three main components, the testfluid supply unit 302, the flow test unit 304, and the control unit 306.In general, the test fluid supply unit 302 stores and supplies a testfluid to the flow test unit 304. The fuel manifold assembly 200 iscoupled to the flow test unit 304, and the test fluid supplied from thefluid test supply unit 302 flows into and through the manifold assembly200 and associated fuel nozzles 114 a-l. The fluid ejected from each ofthe fuel nozzles 114 a-l during the test is collected in one of aplurality of individual measurement vessels 308. The control unit 306periodically samples data from level sensors that are coupled to each ofthe measurement vessels 308, and calculates and displays the flow ratethrough each fuel nozzle 114 a-l throughout the test based on thesampled data. Each of these individual units is discussed in more detailbelow. It is to be appreciated that the test device 300 could beintegrated into a single device, even though it is depicted anddescribed below as three separate units.

[0036] Turning now to FIG. 4, a more detailed discussion of a preferredembodiment of the test fluid supply unit 302 will be provided. As shownin schematic form in FIG. 4, the test fluid supply unit 302 houses,within an enclosure 402 (depicted in phantom), various components usedto supply the flow test unit 304 with test fluid. The first of thesevarious components to be discussed is a test fluid supply tank 404. Thetest fluid supply tank 404 stores the test fluid used during the test.Although the test fluid may be any one of numerous fluids, including jetfuel or water, for safety and testing accuracy, the test fluid used isStoddard solvent MIL-PRF-7024 type II. This test fluid is preferablebecause its physical properties at room temperature, e.g. density,viscosity, etc., are similar to that of jet fuel at the temperature atwhich it operates in a turbofan engine. However, the test fluid has amuch higher flash point than jet fuel for improved safety.

[0037] A pump 406 takes a suction from the test fluid supply tank 404and discharges the test fluid to a fluid manifold assembly 408. Variouscomponents and piping systems are coupled in fluid communication withthe manifold assembly 408. These components include an accumulator 410that helps minimize fluid pressure oscillations within the remainder ofthe system piping. An accumulator dump valve 412 is coupled to the fluidmanifold assembly 408 as well. The accumulator dump valve 412 relievesthe pressure in the accumulator 410 and dumps the fluid back to the testfluid supply tank 404 when the test machine 300 is no longer being used.A safety pressure relief valve 411 is also coupled to the fluid manifoldassembly 408, and is used to relieve fluid pressure in the fluid supplysystem piping back to the test fluid supply tank 404 should the fluidpressure exceed a predetermined pressure setpoint. Finally, a main testfluid supply line 414 is also coupled to the fluid manifold assembly408. This main test fluid supply line 414 directs the test fluiddischarged from the pump 406 to the remainder of the system.

[0038] A plurality of additional test fluid flow lines is coupled to themain test fluid supply line 414 via individual isolation valves. Theseadditional flow lines include a primary supply line 416, a secondarysupply line 418, and a jet-pump bleed line 425. As will be discussed inmore detail further below, the primary supply line 416, which is coupledto the main test fluid supply line 414 by a primary line isolation valve413, directs test fluid to the primary fluid conduits 206 of themanifold sub-assemblies 202, 204 under test. Similarly, the secondarysupply line 418, which is coupled to the main test fluid supply line 414by a secondary line isolation valve 415, directs test fluid to thesecondary fluid conduits 208 of the manifold assembly 200 under test.The primary supply line 416 and secondary supply line 418 each include acoarse and a fine throttle valve coupled in parallel with one another.Specifically, the primary supply line 416 includes a coarse primarythrottle valve 417 and a parallel-connected fine primary throttle valve419. Similarly, the secondary supply line 418 includes a coarsesecondary throttle valve 421 and a parallel-connected fine secondarythrottle valve 423. The primary 417, 419 and secondary 421, 423 throttlevalves are used to adjust the test fluid supply pressure magnitude inthe primary supply line 416 and secondary supply line 418, respectively,during the test. It is to be appreciated that one or more of the primary417, 419 and secondary 421, 423 throttle valves may be eitherelectrically-operated or manually-operated valves. In a preferredembodiment, however, one or more of these valves 417, 419, 421, 423 areelectrically-operated and are automatically positioned by controlsignals supplied from the control unit 306. A pump bypass flow line 422returns pump bypass fluid to the test fluid supply tank 404, through awater cooled heat exchanger 424. It is to be further appreciated thatthe throttle valves may be physically located in either the test fluidsupply unit 302 or in the flow test unit 304. For convenience the valvesare depicted in FIG. 4 with the test fluid supply unit; however, in apreferred embodiment these valves are mounted in the flow test unit 304.

[0039] A flow sensor 426 is preferably coupled to the main test fluidsupply line 414. The flow sensor 426 supplies an electrical signalrepresentative of total test fluid flow being supplied by the pump 406,and may be any one of numerous flow sensors including, but not limitedto, a turbine flow meter, a venturi flow sensor, a thermal flow sensor,or a Coriolis-type flow sensor. As will be discussed further below, thetest fluid flow signal is periodically sampled by the test control unit306 and used to display the total test fluid flow rate in the main testfluid supply line 414. A temperature sensor 427 is placed downstream ofthe flow sensor 426, and supplies an electrical signal representative oftest fluid temperature for sample and display by the control unit 306.The temperature sensor 427 may any one of numerous temperature sensorsknown in the art including, but not limited to, a thermocouple or aresistance temperature detector (RTD). A filter 428 may also be includedin the main test fluid supply line 414 to capture any debris that mayget into the test fluid supply tank 404. A first 430, a second 432, anda third 434 pressure sensor are coupled to the main test fluid supplyline 414, the primary supply line 416, and the secondary supply line418, respectively, via individual isolation valves 436. These pressuresensors each supply electrical signals representative of the fluidpressure within the respective supply lines, and may be any one ofnumerous pressure sensors including, but not limited to, bellowssensors, semiconductor sensors, and quartz sensors. As with the testfluid flow signal, the pressure signals supplied by the first 430,second 432, and third 434 pressure sensors are periodically sampled bythe test control unit 306 and used to display the test fluid pressuresin the main 414, primary 416, and secondary 418 supply lines,respectively.

[0040] Finally, a return line 437 is in fluid communication with thetest fluid supply tank 404 and, as will be discussed in more detailfurther below, returns the test fluid supplied to the flow test unit 304back to the test fluid supply tank 404 aided by a jet-pump 424 driven byhigh pressure fluid in a bleed-line 425 that taps into line 414(upstream of the flow meter). A level sensor 438, which may be any oneof numerous level sensors known in the art including, but not limitedto, a float-type sensor, an optical sensor, or an ultrasonic sensor,supplies an electrical signal representative of at least a minimum testfluid level in the test fluid supply tank 404. As will be discussedfurther below, the output of the level sensor 438, and its concomitantcircuitry, provides an indication on the control unit 306 that a minimumlevel of test fluid is in the test fluid supply tank 404.

[0041] With reference to FIG. 5, a discussion of the flow test unit 304will now be provided. The flow test unit 304, which is depicted insimplified schematic form in FIG. 5, includes a primary supply line 502,a secondary supply line 504, a vent line 506, a return line 508, and theplurality of individual measurement vessels 308. The primary supply line502 and the secondary supply line 504 are coupled in fluid communicationwith the primary supply line 416 and the secondary supply line 418,respectively, in the test fluid supply unit 302. Similarly, the returnline 508 is coupled in fluid communication with the return line 437 inthe test fluid supply unit 302. The vent line 506 is coupled to the topsof each of the individual measurement vessels 308 and vents them toatmospheric pressure so that there is no pressure build-up within themeasurement vessels 308, which would adversely affect testing accuracy.

[0042] Before proceeding with the description of the remainder of theflow test unit 304, a detailed description of an embodiment of one ofthe measurement vessels 308 will first be provided. In doing so,reference should be made to FIG. 6, which depicts a cross section sideview of a single measurement vessel taken along line 6-6 of FIG. 3. Forthe sake of clarity, FIG. 6 does not depict any external componentscoupled to the illustrated measurement vessel 308, except for a leveltransducer. As FIG. 6 illustrates, the measurement vessels 308 comprisean assembly of various components, which includes a substantiallytransparent tube 612 coupled between a nozzle mounting plate 614 and astabilizing mounting plate 616. The tube 612 is substantiallytransparent so that an operator can view the spray pattern of the testfluid emitted from the nozzle portion 117 of each of the installed fuelinjector nozzle 114 a-l. The nozzle mounting plate 614 includes a nozzleassembly mounting clamp 618, and at least two openings. A first opening620 is configured to receive the nozzle portion 117 of one of the fuelinjector nozzles 114 a-l, and a second opening 622 is an air vent. Whena manifold sub-assembly 202, 204 is being tested, the manifold's fuelinjector nozzles 114 a-l are mounted on top of the nozzle mounting plate614, such that the nozzle portions 117 extend through the first opening620. The nozzle assembly clamp 618 is then used to firmly hold the fuelinjector nozzle 114 a-l in place throughout the test. Though notdepicted, the second opening 622 is coupled to the vent line 506. Thestabilizing mounting plate 616 stabilizes the tube 612 and the othercomponents of the measurement vessel 308, which will now be discussed inmore detail.

[0043] A fluid communication tube 624 is coupled between a manifoldblock 626 and the stabilizing mounting plate 616. The fluidcommunication tube 624 receives the test fluid ejected into the tube 612from the nozzle portion 117 of the installed fuel injector nozzle 114a-l, and communicates it to a fluid distribution path 628 within themanifold block 626. The fluid distribution path 628 provides fluidcommunication between the fluid communication tube 614 and a measuringtube 630. The manifold block 626 also includes a drain opening 632 influid communication with the fluid distribution path 628. As will bediscussed further below, the drain opening 632 is coupled, via a valve,to the return line 508.

[0044] Similar to the fluid communication tube 624, the fluid measuringtube 630 is coupled between the manifold block 626 and the stabilizingmounting plate 616. An opening 634 is provided in an end portion of thefluid measuring tube 630, to vent air displaced by the test fluid thatenters the fluid measuring tube 630. Thus, when test fluid is sprayedfrom the installed fuel injector nozzle 114 a-l into the transparenttube 612, the test fluid drains into the fluid communication tube 624.The test fluid in the fluid communication tube 624 then flows into andthrough the fluid distribution path 628 in the manifold block 626. Sincethe fluid measuring tube 630 is in fluid communication with the fluidcommunication tube 624, fluid level in the fluid measuring tube 630 willrise concomitant with the fluid level in the fluid communication tube624.

[0045] A fluid level sensor 636 is mounted to the manifold block 626 andis used to generate electrical signals representative of test fluidlevel in the fluid measuring tube 630. The fluid level sensor 636includes a transceiver 638 coupled to a tube 640 that extendslongitudinally within the fluid measuring tube 630, from a bottomportion 631 to a top portion 633 of the measuring tube 630. The skilledartisan will appreciate that the tube 640 need not extend all the way tothe top portion 633 of the measuring tube 630. Nonetheless, to providethe tube 640 with lateral stability, it is so configured in the depictedembodiment. A magnetic float 642 surrounds the tube 640 and is free tomove along the longitudinal axis of the tube 640, and is buoyant in thetest fluid. Thus, as fluid level rises in the fluid measuring tube 630,the magnetic float will concomitantly rise. It is to be appreciated thatthe magnetic float 642 may be an integral piece that is itselfmagnetized, or may be comprised of separate pieces that provide amagnetic field.

[0046] The fluid level sensor 636 operates on the principle oftime-domain-reflectometry (TDR). Under this principle, the transceiver638 periodically transmits electrical pulses into a conductor 641 (shownin phantom) mounted longitudinally within the tube 640. Each of theelectrical pulses traverses the conductor 641 until it reaches themagnetic float 642. Upon attaining the same position as the magneticfloat 642, the electrical pulse is reflected back toward the transceiver638, due to the pulse's interaction with the magnetic field emitted bythe magnetic float 642. The transceiver 638 receives the reflected pulseand determines the distance to the magnetic float 642 based on the timeit took for the transmitted electrical pulse to be reflected back to thetransceiver 638. An example of one such level sensor is sold by BALLUFF,Inc.®, having a Part No. BTL2-P1-0400-Z-EEXA-KL.

[0047] It is to be appreciated that the fluid level sensor 636 is notlimited to the embodiment depicted in FIG. 6 and described above.Rather, this level sensor is only exemplary of a preferred embodimentdue to its accuracy and sensitivity. Other types of level sensors knownin the art including, but not limited to, resistive sensors and opticalsensors, may also be used. It is to be further appreciated that themeasurement vessels 308 are not limited to the particular depictedconfiguration. Indeed, the measurement vessels 308 could be configuredas single tubes, rather than as an assembly of various components.

[0048] Returning once again to FIG. 5, the discussion of the flow testunit 304 will now be completed. It was previously mentioned that each ofthe manifold blocks 626 that form a part of the preferred measurementvessels 308 include a drain opening 632 coupled in fluid communication,via valves 510, with the return line 508. Although these valves 510 maybe any one of numerous valves known in the art, such as manual valves,solenoid operated valves, or hydraulically operated valves, in thedepicted embodiment the valves 510 are air operated valves. In aparticular preferred embodiment, the valves 510 are so-called “pinchvalves,” sold by Red Valve Company, Inc.®, under part number 2600-3/4BUNA N.

[0049] To accommodate the preferred drain valve embodiment discussedimmediately above, an air supply line 512 is provided to operate each ofthe valves 510. A solenoid operated, valve 514 is coupled in the airsupply line 512 between each of the valves 510 and a non-illustratedsource of 30 psig air. The test control unit 306 controls the positionof the valve 514. When the solenoid is energized, the valve 514 supplies30 psig air to each of the valves 510 causing each to close,.Conversely, when the solenoid is de-energized, the valve 514 vents thevalves 510 to atmosphere, thus opening them, and causing the measurementvessels 308 to drain the collected test fluid back to the test fluidsupply tank 404.

[0050] The control unit 306 is coupled to the various instrumentationand control devices described above and, with reference to FIGS. 7-10,will now be discussed in detail. Turning first to FIG. 7, the overallarrangement of the control unit 306 will first be described. The controlunit 306 houses within an enclosure 700 various devices that are used tomonitor and control the overall operation of the test machine 300. Thesedevices include a computer 702 (shown in phantom), which may be any oneof numerous general-purpose computers, such as a personal computer (PC),or a specially designed computational device. A display device 704 iscoupled to the computer 702 and displays a test-related user interface,which is discussed in more detail below. A printer, though notexplicitly depicted, is also coupled to the computer 702 and is used toprint out test results. Two input devices are also coupled to thecomputer 702. These input devices include a keyboard 706 and a “mouse”708. It will be appreciated that both of the input devices 706, 708 arenot necessary, and that the control unit 306 would be operable if onlythe keyboard 706 were used. The keyboard 706 allows an operator to inputcertain alpha-numeric data into the computer 702 and, if necessary, tomanipulate a screen cursor to control operation of the computer 702should the mouse 708 not be installed or be inoperative. The mouse 708is used to conveniently position the screen cursor to desired positionson the screen of the display 704 to more easily accommodate computeroperations. Finally, various electrical and electronic components 710are also housed within the control unit enclosure 700. These electricaland electronic components 710 provide an interface between thepreviously described instrumentation and control devices and thecomputer 702, and will now be discussed in more detail.

[0051] The various instrumentation and control devices, it will berecalled, include the flow sensor 426, first 430, second 432, and third434 pressure sensors, the fluid supply tank level sensor 438, thetemperature sensor 427, the level sensors 636, the pump 406, theaccumulator dump valve 412, the electrically-operated primary 417 andsecondary 419 throttle valves, and the valve 514. It will be appreciatedthat the flow sensor 426, first 430, second 432, and third 434 pressuresensors, the temperature sensor 438, and the level sensors 636 are eachcoupled to the computer 702 using substantially identical circuitry.Hence, for the sake of brevity, the circuitry associated with only oneof these sensors will be depicted and described in detail. In doing so,attention should now be turned to FIG. 8, which depicts a block diagramof the circuitry 800 associated with each of the level sensors 636.

[0052] The level sensor 636 is coupled, via a plurality of safetybarriers 802, to an instrumentation interface circuit 804 and a powersupply 806. The safety barriers 802 are known protection devices thatoperate on the zener diode principle. That is, the devices limit thevoltage potential across, and thus the current flow through, the deviceto which each is coupled. Thus, the likelihood of any potentially unsafecondition that could be caused by an over-voltage or over-currentcondition to the connected device is substantially reduced. Theinstrumentation interface circuit 804 receives operational power fromthe power supply 806 and converts the signal from the level sensor 636to an appropriate input to the computer, which may be either an analogcurrent level (e.g., 4-20 milliamperes) or a digital value. The powersupply 806 also supplies operational power to the level sensor 636. Itis noted that the power supply 806 may supply power to more than onesensor.

[0053] The instrumentation interface circuit 804 is coupled to aninput/output (I/O) circuit 808, which in turn is coupled to amicroprocessor 810 within the computer 702. The I/O circuit 808 may bean individual I/O circuit dedicated to a single level sensor 636, or amulti-channel I/O circuit shared by several sensors. The microprocessor810 is controlled by software located in a memory 812. The memory 812may either be integral to the microprocessor 810 or, as depicted,physically separate. The software, among other things, controls themicroprocessor 810 to periodically sample the signals transmitted fromthe level sensor 636 to, and through, the instrumentation interfacecircuit 804 and I/O circuit 808. The sampling frequency may be any oneof numerous sampling frequencies, but in a preferred embodiment thesampling frequency is at least five times per second.

[0054] The circuitry used to process the control signal to the pump 406,the electrically-operated primary 417 and secondary 419 throttle valves,and the valve 514, and which is depicted in FIGS. 9 and 10, is similarto that described immediately above. However, as FIG. 9 depicts, thecircuitry 900 associated with the pump 406, and the valve 514, includesa relay circuit 902, rather than an instrumentation interface circuit804, and does not include the safety barriers 802, since all of theleads associated with this circuitry remain within explosion-proofcases. The relay circuit 902 is used to control the position of one ormore relay contacts 904, which in turn selectively controls the supplyof power from a power supply 906 to the device being controlled. Thepower supply 906 depicted in FIG. 9 may be a low voltage power supplysimilar to that depicted in FIG. 8, or may be the main power supply tothe test machine 300.

[0055] The circuitry 1000 associated with each of theelectrically-operated primary 417 and secondary 419 throttle valves, oneof which is depicted in FIG. 10, differs from that of FIG. 8 in that itincludes a driver circuit 1002 rather than an instrumentation interfacecircuit 804. The driver circuit 1002, under control of themicroprocessor 810, supplies power to the electrically-operated throttlevalve 417 (419) to maintain an appropriate test fluid pressure magnitudein the primary (or secondary) supply line 416 (418), as sensed by thefirst (second) pressure sensor 432 (434).

[0056] As was noted above, the display device 704 is coupled to thecomputer 702 and displays information processed within the computer 702.In addition, a printer 818 is preferably coupled to the computer 702 andis used to print out test data processed within the computer 702. Withreference now to FIG. 11, the various types of information displayed andprinted by the display device 704 and printer will be discussed. It willbe appreciated that the fuel manifold test application software run bythe computer 702 is started by, for example, double clicking on an iconon a start-up screen (not illustrated). When this is done, the userinterface screen display 1100 illustrated in FIG. 11 is visible on thedisplay device 704.

[0057] The user interface screen display 1100 includes various displayfields, some of which are modifiable by an operator via the keyboard 706and/or mouse 708, and others of which provide for only the display ofdata. Specifically, the user interface screen display 1100 includes aP/N field 1102, a S/N field 1104, a Technician field 1106, and an R/ONo. field 1108. The P/N field 1102 allows an operator to enter thespecific part number of the manifold assemblies being tested. The S/Nfield 1104 allows an operator to enter the specific serial number of themanifold assemblies being tested. The Technician field 1106 allows anoperator to enter his/her name, and the R/O No. field 1108 allows anoperator to enter the Repair Order number (for accounting/trackingpurposes). Below these interactive fields are a Date display field 1110and a Calibration Due display field 1112. The Date display field 910displays the current date, and the Calibration Due display field 1112displays the date that the next calibration is due for the test machine300.

[0058] Seven so-called “button bars” are displayed below theabove-mentioned fields. These seven button bars include a START button1114, a CONTINUE button 1116, a STOP button 1118, a PRINT button 1120, aCALIBRATE button 1122, a TECHNICIAN LIST button 1124, and a CREATERECIPE button 1126. As will be described more fully below, operating theSTART button 1114 causes the computer 702 to commence a test sequence,operating the CONTINUE button 1116 causes the computer 702 to continueon to another test in the test sequence, and operating the STOP button1118 causes the computer 702 to discontinue a test or test sequence.Operating the PRINT button 1120, as it connotes, causes the computer 702to deliver test result data to the printer 814 for printing. Operatingthe CALIBRATE button 1122 causes the computer 702 to run a passwordprotected calibration procedure, which steps the operator through thecalibration process for the test machine 300. The TECHNICIAN LIST button1124, when operated, causes the computer 702 to run a password protecteddialog procedure which allows the operator to edit a database thatstores the names of technicians that are authorized to run the testmachine 300. In order to run a test with the test machine 300, the nameentered in the Technician field 1106 must match a name in the authorizeduser database. Finally, operating the CREATE RECIPE button 1126 causesthe computer 702 to run a password protected dialog procedure whichallows the operator to edit existing, or create new, “test recipes”stored in a test recipe database in memory 812. The test recipe databaseis a part of the fuel manifold test application software and includesall of the required pressure setpoints and flow tolerances that must bemet during each of the tests. The test recipe database includes an entryassociated with every valid part number that is entered by the operator.Thus, when the part number is entered in the P/N field 1102, thesoftware automatically retrieves the appropriate test recipe from thedatabase. If there are no entries in the recipe database that areassociated with the entered part number, then a message is displayed onthe user interface display screen 900.

[0059] A Supply Pressure field 1128 displays, in psig(pounds-per-square-inch gauge) the pressure sensed by the first pressuresensor 426. A Primary Set Pressure 1130 field displays the pressuresensed in the primary line 416 in psig by the second pressure sensor432, and a Secondary Set Pressure field 1132 displays the pressuresensed in the secondary supply line 418 in psig by the third 434pressure sensorA Fluid Flow field 1134 displays the fluid flow sensed bythe flow sensor 426 in pph (pounds-per-hour). And, a Fluid Temp field1136 displays the fluid temperature sensed by the temperature sensor 427in degrees Fahrenheit.

[0060] Positioned below the above-described pressure, flow, andtemperature display fields are a Pump On/Off button 1138 and a ReservoirOK field 1140. The Pump On/Off button 1138, when operated, turns thepump 406 in the test fluid supply unit 302 on and off. The Reservoir OKfield 1140 indicates that the fluid level in the test fluid supply tank404 is above a minimum required level, as sensed by level sensor 438.Additionally, positioned below the PRINT button 1120 and CALIBRATEbutton 1122 are a Primary Pressure field 1142 and a Secondary Pressurefield 1144 which display the target pressures. These values are providedby the test recipe that is associated with the part number entered inthe P.N field 1102. The largest field in the user interface screendisplay 1100 is the nozzle test data field 1146. Included in this fieldare a Test-Type field 1148, a nozzle Flow Rate field 1150, a numericLevel field 1152, an Initial field 1154, a Difference field 1156, and agraphic Level field 1158. The Test-Type field 1148 displays the type offlow test that is being (or will be) conducted. Thus, as will becomemore apparent further below, the Test-Type field 1148 will displayeither “Primary,” “Secondary,” or “Combined,” to indicate that a primaryflow test, a secondary flow test, or a combined flow test, respectively,is being conducted. Each of the remaining fields in the nozzle test datafield 1146 provides a separate data display for each of the measurementvessels 308 and individual nozzles 114 a-l in the manifold assembly 200being tested. Hence, the nozzle test data field 1146 includes one columnfor each measurement vessel 308 and fuel nozzle 114 a-l in the manifoldsub-assemblies 202, 204. In a preferred embodiment, in which themanifolds consist of twelve nozzles, there are twelve columns in thenozzle test data field. Thus, the nozzle Flow Rate field 1150 displaysthe flowrate (in pph) through each of the nozzles 114 a-l. The numericLevel field 1152 displays the current test fluid volume (in mL) in eachof the measurement vessels 308. The Initial field 1154 displays theinitial test fluid volume (in mL) in each of the measurement vessels 308at the start of a particular flow test. The Difference field 1156displays the difference between the current test fluid volume and theinitial test fluid volume (in mL). And, the graphic Level field 1158graphically displays the current test fluid volume (in mL) in each ofthe measurement vessels 308.

[0061] A test result field 1160 is provided on the user interfacedisplay screen display 1100. The test result field 1160 includes atolerance field 1162 that displays the maximum acceptable percentagedifference in flow rates through each of the nozzles being tested (%Diff_(max)) that comes from the recipe. Above this field is a resultfield 1164 that displays the calculated maximum percentage differencebetween nozzle flow rates based on the data gathered during theparticular flow test. In particular, the software preferably calculatesthe maximum percentage difference between nozzle flow rates (%Diff_(calc)) by subtracting the lowest calculated individual nozzle flowrate from the highest calculated individual nozzle flow rate, anddividing the difference by the calculated median flow rate through allof the individual nozzles. It is to be appreciated that this calculationis only exemplary of a preferred method and that other methods ofdetermining % Diff_(calc) could be employed.

[0062] Finally, there are three indicators positioned between the nozzletest data field 1146 and the START button 1114, CONTINUE button 1116,and STOP button 1118. These indicators are a Check Nozzle indicator1166, a Press a Button indicator 1168, and a PASS/FAIL indicator 1170.The Check Nozzle indicator 1166 prompts the operator to visually checkthe spray pattern of each nozzle. The Press a Button indicator 1168alerts the operator that the software has completed the current test andis waiting for the operator to select the next step. The PASS/FAILindicator 1170 illuminates with the appropriate message, either PASS orFAIL, upon completion of each test in the test sequence.

[0063] The test machine 300 is used to conduct three separate tests onthe fuel manifold assembly 200. As was briefly mentioned above, thesetests include a primary flow test, a secondary flow test, and a combinedflow test. During the primary flow test, test fluid is directed to onlythe primary 212 inlet ports of each manifold sub-assembly 202, 204.During the secondary flow test, test fluid is directed to only thesecondary 216 inlet ports of each manifold assembly 202, 204. Andfinally, test fuel flow is simultaneously directed to both the primary212 and secondary 216 inlet ports during the combined flow test. It isnoted that these tests are preferably conducted in the described order(e.g., primary, secondary, combined), but that the present invention isnot limited to this order.

[0064] Briefly, the fuel manifold assembly 200 is tested by installingeach sub-assembly 202, 204 in the flow test unit 304, such that thenozzles 114 a-l extend through the first openings 620 in each of themeasurement vessels 308. This is accomplished by mounting the manifoldsub-assemblies 202, 204 and nozzles 114 a-l on top of each of the nozzlemounting plates 614, and positioning each of the nozzle assemblystabilizers 618 to firmly hold the injector nozzles 114 a-l in place.The primary 502 and secondary 504 supply lines are then coupled to theprimary 212 and secondary 216 inlet ports of the end fuel nozzles 114 a.Then, with the fuel manifold test application software running, theoperator enters the appropriate data, starts the pump 406, and pressesthe START button 1114 to initiate the primary flow test. When theprimary flow test is completed, the computer 702 calculates and displaysthe maximum percentage difference (% Diff_(calc)) between nozzle flowrates, and provides the appropriate message in the PASS/FAIL indicator1170. The operator then presses the CONTINUE button 1116 to initiate thesecondary flow test. After the secondary flow test is complete, thecomputer 702 once again calculates and displays the maximum percentagedifference (% Diff_(calc)) between nozzle flow rates, and provides theappropriate message in the PASS/FAIL indicator 1170. Thereafter, theoperator once again presses the CONTINUE button 1116 to initiate thecombined flow test. And once again, upon completion of the test thecomputer 702 calculates and displays the maximum percentage difference(% Diff_(calc)) between nozzle flow rates, and provides the appropriatemessage in the PASS/FAIL indicator 1170. It is noted that during each ofthe primary, secondary, and combined flow tests, the operator observesthe spray pattern of the test fluid emitted from each of the nozzles 114a-l. This is possible because of the measurement vessels' substantiallytransparent tube 612. It is additionally noted that upon completion ofthe combined flow test, the test data can be printed out by pressing thePRINT button 1120, and the test machine 300 is ready to begin anothertest cycle.

[0065] Having described the test machine 300 hardware in detail, andhaving very generally described how the software components control thetest machine 300 to carry out the primary, secondary, and combined flowtests, a more detailed description of the flow test methodology carriedout by the software loaded onto computer 702 will be provided. In thisregard, the parenthetical references to “STEPs” in the followingdiscussion correspond to the particular reference numerals of theprocess flowchart depicted in FIG. 12.

[0066] The discussion of the process depicted in FIG. 12 is predicatedon the fact that a fuel nozzle has been installed in the flow test unit304, as described above. After the operator properly installs the fuelnozzle assembly 200, he/she then enters the appropriate part number,serial number, and his/her name in the appropriate fields, and turns thepump 406 on by pressing the Pump On/Off button 1138.

[0067] When the operator presses the START button 1114, the process 1200carried out by the software begins (STEP 1202). At this point, thesoftware checks the P/N field 1102, S/N field 1104, Technician field11106, and R/O No. field 1108 for valid data (STEP 1204). If theinformation entered in these fields is invalid, a message is displayedon the user interface screen 1100 to alert the operator (STEP 1206). If,on the other hand, the information is valid, the process proceeds to thenext step.

[0068] In the next step, the computer 702 retrieves the appropriate testrecipe from the test recipe database (STEP 1208). It will be recalledthat the test recipe database includes a test recipe for each valid partnumber entered in the P/N field 1102. After the test recipe is loaded,the computer 702 positions the valve 514 so that the drain valves 510move to the shut position (STEP 1210). The appropriate isolation valve413 (415) is opened, and the appropriate throttle valves 417, 419 (421,423) are then opened and adjusted until the pressure in the primary(secondary) supply line 416 (418) reaches the required magnitude, assensed by the first (second) pressure sensor 432 (434) (STEP 1212). Atthis point, test fluid is flowing through each of the nozzles 114 a-land is being collected in each of the measurement vessels 308. It willbe appreciated that in an alternative embodiment, in which the throttlevalves 417, 419 are manually-operated, these valves will be adjustedbefore the START button 1114 is pressed.

[0069] In any case, after the drain valves 510 are shut and the supplypressure is adjusted, the computer begins sampling the level signalsfrom each of the level sensors 636. Using the sampled level signals, thecomputer 702 calculates and displays the test fluid volume collected ineach of measurement vessels 308 both numerically (in the numeric Levelfield 1152) and graphically (in the graphic Level field 1158) (STEP1214). The computer 702 monitors each of the measurement vessel levelsand determines if all of the level sensors 636 indicate a change inmeasurement vessel level after a first predetermined time period (STEP1216). If not all of the level sensors 636 indicate a change, it is anindication of a potential fault, either mechanical or electrical innature. As a result the test is discontinued, the drain valves 514 areopened, and an appropriate message is displayed on the user interfacescreen 1200 (STEP 1218).

[0070] If all of the level sensors 636 indicate a level change, the testfluid flow into the measurement vessels 308 continues, and then wheneach of the measurement vessels 308 has collected a first predeterminedvolume of test fluid, as set in the test recipe, the test fluid volumein each of the measurement vessels 308 at that point in time isdisplayed in the Initial field 1154, and the nozzle flow test portionbegins. The test fluid continues to flow through the fuel nozzles 114a-l and into the measurement vessels 308 until one of two events occur.These events are either a second or “final” predetermined test fluidvolume is collected in each measurement vessel 308 (STEP 1220), or asecond predetermined time period has passed since each measurementvessel 308 collected the first predetermined test fluid volume (STEP1222). If the second predetermined time period has passed and the secondpredetermined test fluid volume has not been collected, this isindicative of a potential fault as well. As a result, the test isdiscontinued, the drain valves are open, and an appropriate message isdisplayed on the user interface screen 1200 (STEP 1224).

[0071] Once each of the measurement vessels 308 collects the secondpredetermined volume of test fluid before the second predetermined timeperiod has elapsed, the computer 702 in the control unit 306 stopssampling the signals from each of the level sensors 636 (STEP 1226) andcalculates and displays the maximum flow rate variation (% Diff_(calc))between each of the fuel nozzles 114 a-l in the result field 1164 (STEP1230). In a preferred embodiment, if the calculated maximum flow ratevariation is within the value indicated in the tolerance field 1162,then the result field 1164 is highlighted in green (STEP 1232) and thePASS/FAIL indicator 1170 displays PASS. Conversely, if the maximumcalculated flow rate variation exceeds the value in the tolerance field1162, then the result field 1164 is highlighted in red (STEP 1038) andthe PASS/FAIL indicator 1170 displays FAIL. It is to be appreciated thatother methods of indicating a failed test could also be used, such asdifferent colors, the sounding of an alarm, or a separate messagealtogether. In any case, the data from the test is then stored in memory(STEP 1236), and the drain valves are opened (STEP 1238).

[0072] After the primary flow test, the operator can stop the testing bypressing the STOP button 1118 (STEP 1240), or proceed to the next testby clicking on the CONTINUE button 1116 (STEP 1242). Should the operatorclick on the CONTINUE button 1116, the computer 702 in the control unit306 would initiate the secondary flow test, since the previous test wasa primary flow test (STEPS 1244-1246). The secondary flow test isconducted similar to the primary flow test except that the primary shutoff valve 413 is shut and the secondary shut off valve 415 is opened;and the secondary throttle valves 421, 423 are adjusted to the pressurein the test recipe (STEPS 1210-1238). Thus, test fluid flows only intothe secondary inlet ports 216.

[0073] Upon completion of the secondary flow test, the operator may onceagain stop the testing by pressing the STOP button 1118 (STEP 1240), orproceed to the next test by clicking on the CONTINUE button 1116 (STEP1242). This time, if the operator clicking on the CONTINUE button 1116,the computer 702 initiates the combined flow test, since the previoustest was a secondary flow test (STEPS 1248-1250). The combined flow testis conducted similar to the primary and secondary flow tests except thatboth the primary 413 and secondary 415 shut off valves are open, and allof the throttle valves 417, 419, 421, 423 are adjusted to the pressurein the test recipe (STEPS 1210-1238). Thus, test fluid flows into boththe primary 212 and secondary 216 inlet ports.

[0074] Once the combined flow test is completed the test sequence ends(STEP 1252). At this point, the operator can shut the test machine 300down or replace the manifold assembly 200 just tested with anothermanifold assembly 200. Although not illustrated in the process flowchart1200, the operator may also print out the test results from thecompleted test sequence. A non-limiting example of the content andformat of one such printout 1300 is depicted in FIG. 13.

[0075] The test machine 300, including both its hardware and softwarecomponents, provide significant features and advantages over other fuelmanifold test devices. Most notably, it provides increased accuracy andrepeatability over other devices and methods. It provides real-timelevel sensing and display throughout the test, which other devices andmethods do not provide. Operators can view the fuel nozzle spraypatterns throughout the flow test sequence. Additionally, the testdevice is configured as a closed loop system.

[0076] While the invention has been described with reference to apreferred embodiment, it will be understood by those skilled in the artthat various changes may be made and equivalents may be substituted forelements thereof without departing from the scope of the invention. Inaddition, many modifications may be made to adapt to a particularsituation or material to the teachings of the invention withoutdeparting from the essential scope thereof. Therefore, it is intendedthat the invention not be limited to any particular embodiment disclosedfor carrying out this invention, but that the invention includes allembodiments falling within the scope of the appended claims.

We claim:
 1. A computer-readable medium storage medium containing computer executable code for instructing a computer, which is coupled to a test stand that is configured to test fluid flow distribution through a turbine engine fuel manifold and one or more fuel nozzles, and that includes a plurality of fluid measurement vessels each operable to receive a test fluid discharged from one of the fuel nozzles, to perform the steps of: periodically determining and displaying a volume of test fluid discharged from each of the fuel nozzles until each of the measurement vessels have collected a predetermined volume of the test fluid; and periodically calculating and displaying test fluid flow rate through each of the fuel nozzles based on the periodically determined test fluid discharge volume. 